Hello,
I am new here, and I am a newbie to DIY audio as well...:-)))
I am turning to you guys for help with my Crack build. The resistance check of the circuit was OK. When I put in the tubes and switched it on, only the 6080 would glow, the 12AU7 would not. My first assumption was that maybe the tube does not have to show a visible glow. Therefore, I proceeded to the voltage checks and got the following voltages:
Terminal Voltage expected Voltage measured
1 90 0
2 170 0
3 0 0
4 170 0
5 90 0
6 0 0
7 100 53
8 0 0
9 100 55
10 0 0
11 0 0
12 0 0
13 170 155
14 0 0
15 185 166
20 0 0
21 206 175
A1 90 0
A2 0 0
A3 1.5 0.14
A4 0 0
A5 0 0
A6 90 0
A7 0 0
A8 1.5 0.14
A9 0 0
B1 90 0
B2 170 137
B3 100 55
B4 90 0.1 - 0.3 (fluctuating)
B5 170 157
B6 100 56
B7 0 0
B8 0 0
I would appreciate any help with this as I have re-checked all wires and they seem OK to me. Should the 12AU7 exhibit a noticeable glow? Could that tube be broken?
Thanks very much in advance.
Falko